UV Water Filters – What are they, how do they work?
Ultraviolet water filters are recognised in the water filtration industry as one of the best alternatives to water chlorination. Whether you want to treat water sourced from a private well or you’re looking to sanitise municipal water, UV water filters can be an excellent choice for destroying 99.99% of waterborne pathogens.
In this basic guide to UV water filters we discuss how UV water filters work, what are the parts of an UV water filter, and what are the pros and cons you should consider before buying one for your home.
How Does UV Filtration Work?
Lying between visible light and X-rays on the electromagnetic spectrum, ultraviolet light is invisible to us, although we are exposed to it every time we step out into the sun.
UV water filters use special UV lamps that emit UV light or rays at a certain wavelength that is capable of sanitising water by disrupting the DNA of microorganisms, so that they are no longer able to infect or reproduce.
The frequency at which these wavelengths are capable of destroying pathogens is called germicidal frequency, and it’s situated at 254 nanometres. UV water sanitation is a simple and effective alternative to water chlorination.
An UV water purification system can destroy cysts, viruses, bacteria, coliform, Salmonella, Giardia, Cryptosporidium, E. Coli, typhoid fever, flu, cholera, dysentery, and many other microorganisms that are harmful to humans.
UV water filters don’t add anything to water, are not harmful in any way for your family or pets, and they don’t alter the taste of water.
Also Read: Are UV water filters safe?
The Parts of an UV Water Filter
Different types of UV water filters come with different components, but most UV water filters have the following parts:
- UV bulb or light: this is the element of the UV sanitising system that produces the UV light at germicidal frequency. This is also the part of the UV water filter that needs to be replaced, just as you would replace a water filter cartridge in a water filter system;
- UV quartz sleeve: it’s a cylinder-shaped tube made of quartz glass, which lets the UV light pass through into the water. It protects the electrically powered UV bulb from the flow of water. The quartz sleeve must be kept clean, so that the UV light can easily pass through the tube. When it can no longer be cleaned or if it breaks, it must be replaced;
- UV chamber: this part controls the flow of water, and houses the quartz sleeve with the UV lamp;
- UV controller unit: depending on the type of UV system you have, it can be more complex – with alarms, lamp change alerts, etc. – or a simple controller that controls the electrical output of the bulb and the wavelength needed for water purification;
- UV sensor: monitors the intensity of the UV light, automatically shutting down the system if the UV light intensity is low (it’s an optional element);
- Solenoid valve: automatically shuts down the system in case of malfunctions, preventing untreated water to flow through the system;
- UV pre-filtration system: although not an integral part of an UV system, an UV pre-filtration unit is necessary for any UV water filter system. UV pre-filters are essentially sediment filters that pre-filter water removing sediments that could block UV lights from reaching microorganisms.
Advantages and Disadvantages of UV Water Filters
As a water disinfection method, UV water filters have many advantages and fewer disadvantages compared to chlorination or adding chloramine to water.
As for the advantages of UV water filters, here are the most significant ones:
- Safe & Chemical-free: an UV water filter disinfects water in a safe, contained environment, adding nothing to your water;
- Eco-friendly: with no disinfection by-products and no chemicals added to water, UV filters are an environmentally friendly alternative to water chlorination;
- Efficient even against chlorine-resistant bacteria: some pathogenic bacteria have become chlorine-resistant, making it increasingly difficult to destroy them. UV lights are efficient even when it comes to destroying chlorine-resistant microorganisms like E. Coli or Cryptosporidium;
- Conserves water: unlike a reverse osmosis system, for example, an UV water filter does not waste any water;
- Does not alter the taste and odour of water;
- Easy to maintain: apart from an annual lamp change and quartz sleeve cleaning, an UV water filter is essentially a set-it-and-forget-it type of system;
- Fast: water is sanitised as it flows through the UV chamber, no water tank or reaction times are necessary.
Undoubtedly, an UV water filter is one of the most reliable and easiest ways to disinfect water, yet an UV water purifier is not without its disadvantages:
- Ineffective against other water contamination issues: UV water filter only address microbiological issues, and are unable to remove any other contaminants like heavy metals or volatile organic compounds;
- UV water filters are ineffective if water is high in sediments: because suspended solids can shield bacteria from UV lights, a sediment pre-filter is a must for every UV water filter system;
- UV water filters require electricity: unlike gravity water filters or pressure filters, UV water filter require electricity to operate, thus, they cannot be used in areas with no electricity.
Most water filter systems will address various water contamination issues. For example, a reverse osmosis system can remove heavy metals, fluoride, chlorine, its by-products, bacteria, and many other contaminants. As opposed to this, an UV filter will only deal with bacterial contamination, and other water filters should be used in conjunction with an UV filter to deliver a thorough filtration.
UV water filters are compatible with other filtration systems, so you can use it in combination with these.
Even though UV water filters can target only a single water contamination issue, they are the best when it comes to solving microbiological contamination problems. UV water purifiers can be installed at a single point of use or as a point-of-entry water filter, and they are most often used in residential settings to disinfect water sourced from private water wells, or in commercial settings, in the water bottling industry.